1. Field of the Invention
This invention relates to an improved screwdriver. More specifically, the invention relates to a hollow handled screwdriver with a pivotally reversible blade adapted to engage the handle in a non-linear manner such as to enhance the manual application of torque.
2. Description of the Prior Art
The basic concept of providing an otherwise conventional screwdriver with a replaceable blade or tip such that one handle will serve for various sizes and types of screwdriver tips is generally recognized and known in the art. Thus, it is known to provide a screwdriver handle with a blade that is held in position by a ball and detent or other mechanical structure such that the blade can be withdrawn and inverted and then reinserted into the handle backwards. In this manner, one screwdriver can be equipped with two different tips (frequently a Phillips and a conventional tip). It is also generally known that screwdrivers with either a ball and detent mechanical socket or magnetic assisted socket at the end opposite the handle can be used with compatible snap-in/snap-out tips wto produce a more versatile hand tool.
Historically, various other types of multiple tips screwdrivers have been suggested and employed with varying degrees of success. For example, in U.S. Pat. No. 161,056 a screwdriver with a flat shaft and pivotally attached dual tip blade is disclosed wherein either of two blades can be pivoted into position and clamped colinerar to the shaft for what would otherwise correspond to a conventional screwdriver usage. In U.S. Pat. No. 750,182, this pivoting dual tip concept is incorporated into a yoke that slides in and out of the handle of a screwdriver. When the yoke is fully extended out of the handle, the pivoting motion of the dual tip element can be used to select which tip is desired and then the entire yoke and pivoting tip element can be retracted back into the handle for conventional use of the screwdriver. In U.S. Pat. No. 1,552,361, a similar combination tool is disclosed wherein the entire blade pivots in and out of the handle about an axis at the midpoint of the hand tool (i.e., one end of the handle) wherein one end of the blade is a screwdriver and the other end is a putty knife. The handle is further equipped with a locking mechanism that retains the blade at the selected configuration. In U.S. Pat. No. 1,695,949, a duplex screwdriver is disclosed similar to the previous combination screwdriver/putty knife, except the locking mechanis is a concentric sleeve that slides to the top of the screwdriver handle to allow the rotation of the pivotally attached dual blade. In a similar manner, U.S. Pat. No. 2,656,865 discloses a dual bladed screwdriver wherein the blade pivots on an axle allowing one blade to be pivoted into the handle while the other extends in a colinear fashion analogous to the conventional screwdriver. This tool further provides for a ratchet type handle and the ability for the screwdriver blade to be held perpendicular to the handle. And in U.S. Pat. No. 3,013,594, a multiple screwdriver is disclosed wherein a dual tipped pivoting blade extends from and recedes into a hollow handle wherein in the extended configuration the dual blade can be pivoted such as to select the desired tip.
Although these prior art screwdrivers are categorically multiple tip screwdrivers and although many of them possess certain specific advantages and features, none of the prior art devices disclosed are multiple tip screwdrivers that combine both conventional colinear blade and handle orientation during operation with a blade that can be held oblique to the handle for improved manual application of torque. As such, the devices are not readily amenable to one handed operation or use by a party that has had a hand or arm amputated or similar disability.